Field of the Invention
The present invention relates to a process for preparing cyclododecanone, to a process for preparing laurolactam and to a process for preparing nylon-12.
Discussion of the Background
Cyclododecanone (CDON) is used for the synthesis of laurolactam. The lactam in turn is suitable for the preparation of nylon-12.
The preparation of CDON may proceed from cyclododecatriene (CDT). First of all, a selective hydrogenation of cyclododecatriene (CDT) to cyclododecene (CDEN) may be undertaken. This is followed by an epoxidation of CDEN to epoxycyclododecane (CDAN epoxide) and the rearrangement of CDAN epoxide to cyclododecanone (CDON). Proceeding from CDEN, the CDON synthesis comprises the following steps:                a. epoxidizing cyclododecene (CDEN) to epoxycyclododecane (CDAN epoxide) and        b. rearranging the CDAN epoxide to CDON to obtain a mixture comprising CDEN.        
The mixture (CDON-containing mixture) which is obtained from the rearrangement thus comprises at least CDON and CDEN.
In this process for preparing CDON, the problem occurs that significant amounts of CDEN can arise. This problem is aggravated by the ageing of catalysts which may be used. The amount of CDEN obtained may be more than 5 by weight, based on the resulting CDON-containing mixture from the rearrangement.
The high proportion of CDEN may have adverse effects on the downstream reactions such as the preparation of laurolactam. In addition, small product yields are comparatively uneconomic.